1. Field of the Invention
This invention relates to a device for limiting the noise level of a fuel burning engine as exhaust gases pass through the exhaust pipe and are expelled to the atmosphere. The invention muffles and deflects sound waves generated by the engine as exhaust is produced and expelled and allows exhaust gases to escape with minimal back pressure on the exhaust system.
2. Description of the Prior Art
A muffler or sound suppressant is a common device used in most types of internal combustion engines. While several devices are known which accomplish some reduction in engine noise, no device is known which accomplishes all of the objectives of the disclosed invention, that is to provide an efficient noise reducing apparatus, which minimizes manufacturing costs and is easy to install. The present invention also minimizes the back pressure associated with diffusion of the exhaust gases.
Known to the applicant is Lyman, U.S. Pat. No. 4,109,753. Lyman discloses a muffler assembly which includes a single flow control means such as a diffuser having a centrally disposed baffle with radially extending deflection vanes and with axially extending tabs. The deflector vanes are twisted to define an angle of deflection varying from 35.degree. to 55.degree. to diffuse the air flow going into the main component. However, the primary means of noise reduction is sound attenuating material such as glass fiber surrounding the exhaust pipe. Diffusion of the exhaust in the manner disclosed also creates back pressure on the exhaust system with more back pressure created as the number of deflector vanes are increased.
None of the known prior art however, accomplishes all of the objectives of the present invention. The disclosed invention provides a sound suppressant for an exhaust system which is placed in the exhaust pipe rather than the tail pipe of an exhaust system which greatly reduces the noise level of the engine. The symmetry and simplicity of design provides a substantial reduction in cost and installation time of the present muffler device over the known prior art.